Pipelaying appliance

ABSTRACT

A pipelaying appliance (1) is removably connected to the bucket (2) of an excavator with the aid of a gripping means (3) mounted on the bucket. The appliance includes two gripping arms (7, 8) of which one thrusts into the pipe (9) and the other is situated on the outside of the pipe. The gripping arms are movable to and from each other and are connected to the appliance so that the clamping force of the gripping arms on the pipe wall will be proportional to the weight of the pipe carried by the appliance.

DESCRIPTION

1. Technical Field

The present invention relates to a pipelaying appliance connected to araisable and lowerable apparatus such as an excavator or a crane, andincluding a gripping means for removable engagement with a pipe.

2. Background Art

In pipelaying different types of gripping scissors are used for holdingthe pipe, these scissors hanging freely in slings or on the safety hookof an excavator. These gripping scissors must be manually coupled up to,and uncoupled from the excavator, and manual work is also required toconnect the scissors to, and remove them from the pipes. The manualconnection is done by a person standing on the ground, and the aligningof a pipe in the pipe trench and the removal of the gripping scissors iscarried out by this person when he has got down into the trench. Afterhaving joined the pipe to a previously laid pipe with the aid of aspecial lever means, the person gets up out of the trench again andreleases the scissors from the excavator so that the latter can continuewith excavation.

This procedure is both time-consuming, labourious and uneconomical.Furthermore there are large accident risks, since the heavy pipes cansway unchecked during the movement to, and lowering into the pipetrench.

DISCLOSURE OF INVENTION

One object of the present invention is to do away with the disadvantagesburdening previously known pipelaying appliances, and to provide anappliance gripping a pipe with a force corresponding to the weight ofthe pipe, which eliminates damage to light pipes and also that heavypipes are gripped with insufficient force, the machine operator himselfbeing able to couple the appliance to, and uncouple it from the machine,perform the necessary operations himself for gripping a pipe, take itdown into an excavated trench, e.g. one parallel to or right angles tothe excavating direction, align the pipe in the trench and thereafterrelease the pipe.

This object is achieved by the invention being given the characterizingfeatures disclosed in the claims.

DESCRIPTION OF FIGURES

FIG. 1 is a schematic side view of a pipelaying appliance in accordancewith the invention, connected to an excavation bucket provided with agripping means and in position for gripping a cement pipe, and

FIG. 2 is a side view similar to the one in FIG. 1 but with theappliance gripping and lifting the cement pipe.

PREFERRED EMBODIMENT

The appliance I illustrated in the Figures is intended to be gripped bya gripping means mounted on a raisable and lowerable apparatus, e.g. acrane or an excavator of the kind illustrated in the Swedish PatentSpecification No. 7714027-5. In the Figures, the raisable and lowerableapparatus is illustrated in the form of a portion of the mentionedexcavator bucket 2 with a gripping means 3 comprising two fingersmovable to and away from each other which are pivotably mounted on theback of the bucket.

The appliance 1 comprises a bar or upright 4 suitably provided with acircular cross section, which can be gripped by the gripping means 3,independent of how the upright is rotated round its longitudinal axis,the bar being provided with an upper plate 5 intended to engage with aportion thereof against the upper surface of the bucket 2 to prevent theappliance from sliding downwards between the fingers 3 when theappliance carries a heavy pipe. At the lower portion of the upright 4,projecting somewhat farther from the bucket 2 than the upper portionthereof, so that the machine operator will be able to see the remainingpart of the appliance better during pipelaying, there are pivotablymounted the first ends of a link 6 and a gripping arm 7. The other endof the link 6 and an intermediate portion of the gripping arm 7 arepivotably mounted in the vertical arm 8a of an L-shaped arm 8. The fourjournalling points constitute the corners in a parallelogram formed bythe details just described, this parallelogram being variable betweenthe shapes illustrated in FIGS. 1 and 2. The horizontal arm 8b of thegripping arm 8 and the somewhat downwardly angled right-hand portion 7aof the gripping arm 7 form the jaws in the means gripping a cement pipe9.

A spring means, suitably a so-called gas spring 10, is pivotably mountedon, and extends between the lower portion of the upright 4 and the upperpart of the arm 8a. The pressing force in the spring 10 is somewhatgreater than the sum of the weight of the link 6, arm 7 and arm 8, so asto keep the jaws 7a and 8a in the open position illustrated in FIG. 1.

When a length of trench in which it is intended to lay cement piping isexcavated by the bucket 2, the bucket is manoeuvered by the machineoperator so that it is moved to the appliance 1, lying or upright on theground at the side of the trench, the gripping means 3 then being openedand caused to surround and grip the upright 4 of the appliance, thebucket then being lifted and turned so that it and the appliance assumethe attitude illustrated in FIG. 1. The appliance 1 is then aligned sothat the arm 8b of the gripping arm 8 is inserted in the end of thecement pipe 9 having an enlarged flange 9a, and the gripping arm portion7a is moved to a position on the outside of the pipe opposite the arm8b. The arm 8b is inserted into the pipe until a rubber-covered portionof the arm 8a comes against the flange 9a.

The bucket 2 is now raised, whereon the arm 8b is lifted into contactwith the inner wall of the pipe 9 and is pressed against it, the springmeans 10 thus being compressed by a force corresponding to thecompressing force. When the compressing force has been surmounted, thegripping arms 7 and 8 and remaining portions of the appliance assume thepositions illustrated in FIG. 2, with the rubber-covered arms 7a and 8bexercising a light clamping action on the pipe wall.

In continued raising of the bucket 2, the pipe 9 is lifted by the arm8b, it and the arm 7a still keeping the positions illustrated in FIG. 2,and are pressed against the pipe wall by a force corresponding to theweight of the pipe. This is important, since a large clamping force isrequired to retain heavy pipes, and since smaller and more frangiblepipes must not be subjected to clamping forces so large that they break.To improve retention of the pipe, the arm 7a should be somewhatinclined, so that it engages against the pipe in the area where theflange 9a merges into the cylindrical pipe wall. The rubber cladding onthe arms 7a and 7b increases the friction between these and the pipe,thereby improving retention, as well as preventing the pipe from beingdamaged.

The bucket 2 is then swung in the horizontal plane to a position abovethe trench, and the bucket lowered into the trench such that the grippedpipe will be in line with pipes previously laid in the trench. Thebucket is then moved forwards (to the right in FIG. 2) so that therighthand end of the pipe is inserted in a pipe the same as the pipe 9.After the pipe 9 has been inserted in the previously laid pipe, thebucket 2 is lowered, for separating the arms 7a and 8b from each otherand releasing their grip on the pipe wall. If the pipe 9 is to be thrustfurther into the previously laid pipe, the bucket can be manoeuvered sothat the rubber cladding on the arm 8a presses the flange 9a to theright.

The appliance 1 is now removed from the pipe 9 and can be used to lay afurther pipe in the trench, or it can be uncoupled from the bucket byopening the gripping means 3 and laid on the ground adjacent the trenchfor use when one or more new pipes are to be laid in a further portionof the trench excavated by the bucket.

Although only one embodiment of the invention has been shown anddescribed, it should be understood that the invention is not limited tothis embodiment but only by the disclosures in the claims.

I claim:
 1. A pipelaying appliance, connected to a raisable andlowerable apparatus such as an excavator or a crane, and including agripping means for removable engagement with a pipe, said meanscomprising a first member projecting into the pipe and an opposingsecond member on the outside of said pipe, said first and second membersbeing movable to and from each other and connected to said appliance sothat the clamping force provided by said first and second members on thewall of said pipe will be proportional to the weight of said pipecarried by said gripping means, characterized by a spring means exertinga force on both said first and second members for the mutualdisplacement thereof when they are not in engagement with said pipe, theweight of which substantially exceeds this force, wherein the firstmember is L-shaped with a substantially horizontal arm engaging saidpipe and a substantially vertical arm parallel to a third member on saidappliance, said third member being connected to said raisable andlowerable apparatus and movably connected to said vertical arm via alink and a portion of said second member parallel to said link. 2.Appliance as claimed in claim 1, characterized in that the angularattitude of said first member relative to the horizontal plane issubstantially unaltered during its insertion into, and support of saidpipe.
 3. Appliance as claimed in claim 1, characterized in that saidsubstantially horizontal and vertical arms engaging with said pipecarried by said gripping means are clad with elastic material. 4.Appliance as claimed in claim 1, characterized in that said third membercomprises a rod or bar which can removably be gripped by a secondgripping means mounted on an excavator independent of how said rod orbar is turned around its longitudinal axis.
 5. Appliance as claimed inclaim 1, characterized in that said spring means acts between said firstmember and said third member.
 6. A pipelaying appliance, connected to anexcavator bucket and including first and second gripping means saidfirst gripping means for removable engagement with a pipe, said firstgripping means comprising a first member projecting into said pipe andan opposing second member on the outside of said pipe, the members beingmovable to and from each other and connected to said appliance so thatthe clamping force provided by said first and second members on the wallof said pipe will be proportional to the weight of said pipe carried bysaid first gripping means, at least one of said first and second membersbeing connected to a bar to be removably gripped by said second grippingmeans mounted on said excavator bucket and remotely controlled by theexcavator operator whereby said bar and said appliance will assume oneof an infinitely variable number of positions in relation to saidexcavator bucket.